Using hospital beds more efficiently could save the NHS in England at least £1 billion a year and deliver benefits for patients, according to a new study.

Currently, more than 70% of hospital bed days are occupied by emergency admissions, and while only 10% of these patients stay for more than two weeks they account for 55% of bed days, says the report, from health policy think tank The King's Fund.

Moreover, 80% of emergency admissions who stay for more than two weeks are patients aged over 65, which suggests that focusing on reducing the length of stay for older people has the most potential for reducing hospital bed use, it says.

Typical diagnoses among older patients with very long length of stay include stroke, hip fracture, pneumonia, urinary disorders, dementia and delirium. Patients who are fit for discharge but remain in hospital are at risk from hospital-acquired infections, while many find prolonged stays frustrating or distressing and, for some, longer stays can lead to depression or loss of functional independence, the authors note.

Recent studies suggest that, for 42%-55% of NHS hospital bed days in England, an alternative setting - which could include medical services provided at home or a nursing home - would be more appropriate for the patient. This would also save money, as acute hospital care costs about £200 a day compared with under £100 for private nursing home fees. But to realise this opportunity, other services such as social and community care must be in place, says the study.

The NHS Institute for Innovation and Improvement estimates that the NHS in England could save just over £1 billion a year by reducing length of hospital stay for both elective and non-elective admissions. However, NHS or social care commissioners need to pay for the alternatives and, under current funding arrangements, it can be difficult for these to be provided, the authors note.

The NHS - including providers of acute and community care and commissioners - and their partners in social care need to work together and adopt a renewed focus on bed use and length of stay, and make changes to facilitate discharge, they say.

Particularly for the elderly, this will require changes to how they are cared for in hospital, eg, by mobilising them early and keeping them mobile, and improving the diagnosis and treatment of delirium and dementia. Hospitals must also work with other organisations - social services, community and domiciliary care and primary care - to ensure timely discharge, says the report, which emphasises: "all these providers must work together if patients' length of stay is to be reduced."